"Bartowski, what's your status?"

Casey's earpiece crackled softly in his ear as Chuck answered him. "I am approaching the vault."

Casey grunted as though in affirmation. He glanced quickly over his shoulder to make sure his partner was still close behind him—just far enough to catch the blonde of her hair in his periphery—and crept closer to the corner they hid behind, weapon drawn close to his chest. His earpiece crackled again, the static louder this time.

"Two guards in the corridor," Chuck informed.

Casey released his gun with his left hand and held his wrist to his mouth. "Be careful, Bartowski. We're getting interference on your end." He waited, but there was no reply.

"What does that mean?" Walker whispered from behind him.

Casey grunted again, his apprehension clear. "Could mean anything. Ready, Walker?"

"Ready."

Casey peered around the corner swiftly, taking notice of the three black-suited men down the hall, before he retreated behind the corner again as quickly as he could. An well-rehearsed stealth move; if any of the guards had spotted him, he was momentarily protected. He waited a split second for their reaction. None came. He turned his chin over his shoulder again and whispered, "Three guards, end of the hall." He adjusted his feet under him. "Come on, Bartowski," he grunted between his teeth.

He heard Walker's intake of breath and felt his eyes roll slightly of their own accord. Typical. It was just like Walker lately to hold her breath for Chuck instead of focusing on her own end of the mission.

Static barked in his ear. "-uar-n-al-z'd."

Walker's panted out a short, anxious breath, but Casey couldn't let himself think about it much. It was time to move.

"Focus, Walker. Let's do this." He took a steadying breath of his own and darted into action. With hard-trained accuracy and precision, they fired their silenced weapons down the hall at the guards. The men turned quickly as the agents rounded the corner, each reaching for his own weapon, but it didn't matter; the element of surprise worked in the agents' favor, and all three men fell to the ground with varying grunts.

Casey and Walker ran silently down the hall. Casey aimed his weapon once more at one of the guards, who was still stirring and groaning on the floor, and silenced him with a clean shot to the head. They continued past them without stopping until they reached the next corner, taking up their defensive position anew before they repeated an identical maneuver on two more guards down the next hall.

As Casey and Walker reached their latest victims-their final obstacle before Keuer's office-Walker dipped down beside one of the men and pulled a blood-splattered ID card off the front of his suit. She passed it quickly to Casey and immediately placed her hand on the door handle. With a quick glance between them, Casey scanned the card over a black scanner pad to the side of the door and dropped the card, gripping his firearm in both hands once again. Walker turned the handle, pulling it open, and Casey moved inside.

Casey quickly scanned the right side of the room, floor to ceiling, looking for more guards, and found none. Behind him, he trusted that Walker had done the same to the left. He turned toward the large, ornate desk at the rear center of the office, noting that although Keuer was nowhere to be seen, his office chair was still spinning from it's occupant's hasty departure mere moments before. His eyes were drawn immediately to an open door in the far right corner: Keuer's only possible escape.

Casey and Walker approached the exit quickly in pursuit of Keuer. Casey held his transmitter to his mouth again as he ran. "Bartowski! Update!" He came to the door and faced an uncomfortably narrow hallway, rather industrial in nature, constructed of unpainted cinderblock walls. Walker close behind him, he ran several more steps, waiting for Chuck's response. It never came.

The apprehension in his gut turned sharply into a knot. "Bartowski! Keuer's making an escape. Do you have the hard drive or not?"

He slowed slightly as he reached the corner in the narrow hallway. He turned his body before he cleared the end of the wall, feet crossing swiftly one over the other to carry him sideways whilst squaring his shoulders toward his target, anticipating a shootout. He aimed carefully down the sights, automatically sweeping his aim steadily from one side of the hallway to the other, but this side of the hallway was empty, too. He picked up the pace again, running as quickly as he could without compromising his grip on the weapon, until he reached the end of the hallway where it widened to accommodate a staircase; one flight of stairs ascended toward the roof, and the other descended to the floors below.

Chuck still had not checked in. It had been far too long since he'd last communicated with the rest of the team, and Casey knew immediately that that meant trouble. Which fashion of trouble, he could only guess, but his felt the hairs on the back of his neck start to lift, a slight tingle running upward toward his crown.

"Should we split up?" Walker panted out as they came to a stop at the stairwell. "You go up, and I'll go down."

Casey grunted. He didn't know how to respond. Should they stay together for backup and support, or accept a heightened risk while increasing the likelihood of apprehending their target?

What a stupid question, he chastised himself. He had always taken pride in his "country-first" attitude. If there was a greater chance to catch Keuer if they separated, then that was undoubtedly worth the greater risk.

"Split up," he affirmed. "If we don't catch him now, we won't catch him at all. And Walker?"

Walker halted a few steps down and looked up at him, several steps up.

"Apprehend Keuer. We'll save Bartowski afterwards."

Walker's expression hardened.

Casey growled. There was no time for this. "If Keuer is on the roof, then you can go find Chuck," he ground out, every syllable wrapped in cynicism. "If he's not, you go find Keuer, and I'll catch up to you."

Sarah nodded curtly, her lips pressed together in a thin line; then she turned and hurried down the stairs. Casey grunted in vague disapproval and pushed Walker and Bartowski to the rear his mind. He had to. His gaze and his aim returned up the stairs, feet taking two steps at a time. He rounded the landing and saw a heavy steel door at the top of the flight. His face stiffened into a growl as he aggressively pounded up the stairs. He reached for the knob and simultaneously threw his weight into the door.

The door gave way immediately, swinging open onto the rooftop. Casey hurried to raise his weapon as he passed through the doorway, but he never got it all the way up. Without warning, something hard and heavy collided with his temple.

His vision blacked out. His knees gave under his weight. His weapon dropped from his hands, and he felt the cold gravel rooftop meet the side of his face.